GB1600088A

GB1600088A - Silo

Info

Publication number: GB1600088A
Application number: GB24879/78A
Authority: GB
Original assignee: Claudius Peters AG
Current assignee: Claudius Peters AG
Priority date: 1977-06-18
Filing date: 1978-05-31
Publication date: 1981-10-14
Also published as: IT1095294B; FR2394474B1; ATA440978A; DE2727499B2; DE2727499A1; FR2394474A1; IT7824244A0; US4184774A; AT355998B

Description

PATENT SPECIFICATION

( 11) r O ( 21) Application No 24879178 ( 22) Filed 31 May 1978 00 ( 31) Convention Application No.

c 22727499 ( 32) Filed 18 June 1977 in c ( 33) Fed Rep of Germany (DE) ( 44) Complete Specification published 14 Oct 1981

1 ( 51) INT CL 3 B O l F 13/02 w ( 52) Index at acceptance Bl C 11 30 5 6 9 ( 72) Inventor WERNER KRAUSS ( 54) SILO ( 71) We, CLAUDIUS PETERS AKTIENGESELLSCHAFT, a body corporate organised under the Laws of the German Federal Republic, of 1 Kapstadtring, D-2000 Hamburg 60, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

This invention relates to silos for loose material, which have therein a homogenising chamber to which the loose material can be fed by means of fluidisation in gas passing into the chamber.

In known mixing silos (e g as described in German Patent No PS 15 07 888) and silos having a central homogenising chamber (e g as described in German Patent Applications P 2657 596 2 and P 26 57 597 3) loose material is fed into the main silo chamber from its top The material is premixed in the main chamber by mixing swirls caused by flow of material from that chamber to the homogenising chamber In the homogenising chamber intensive mixing then occurs The premixed loose material is fed into the homogenising chamber from the bottom through openings in the periphery of the chamber.

By suitably controlling the supply of air a communicating action is achieved between the main silo chamber and the homogenising chamber in dependence on the weight of the material above the air passing into the homogenising chamber and on the flow behaviour of the loose material at any particular moment, as a result of which action the homogenising chamber is filled to a specific level.

Experience with a large number of mixing silos of this kind which are in operation has shown that very good operating results can be obtained The compact construction, low energy consumption, and the elimination of intermediate transport, which is otherwise customarily required, contribute towards economy.

In order to enable optimum mixing to be achieved, it is however necessary that before a silo of this kind is constructed the dimensions of the silo, the rate of mass throughflow, density, fineness of the loose material and the air retaining capacity and flow behaviour of the material, particularly 55 of the pulverulent fraction of the latter, should as accurately as possible match the pneumatic system to be used Once the dimensions of the silo, and particularly of the homogenising chamber, have been de 60 termined and the silo has been constructed in accordance with these dimensions, the specific level to which the homogenising chamber is filled can be subsequently corrected only by means of controlling the gas 65 supply and the pressure difference between the chamber and the rest of the silo.

Although for many applications we have found this adequate, we have nevertheless found cases where such subsequent correc 70 tion is either completely or partially impossible We have found cases in which for reasons of limiting the investment for the construction of the silo, or because of variations of the rate of mass throughflow or 75 behaviour of the loose material which may perhaps come to light only subsequently, circumstances occur as the result of which optimisation of the quality of the mixing can no longer be achieved by controlling the 80 air supply.

According to the present invention there is provided a silo, for loose material, having ventilation means for fluidising said loose material; inlet channels through which 85 fluidised loose material is arranged to pass to a homogenising chamber in the silo, each inlet channel having a valve, the homogenising chamber having a passage therearound having an entrance to the outside of 90 the silo and providing access to the valves.

By means of the valves, which in a preferred embodiment can be operated from the passage, one or more inlet channels to the central chamber may, as required be com 95 pletely or partially closed Instead of controlling air supply to control the flow of material, control of the flow of material can thus be achieved by mechanical means It is thus possible for corrections in respect 100 1 600 088 1 600088 of the matching of the dimensions of the silo, rate of mass throughflow, density of the loose material, and so on, that is to say corrections which could not necesarily be made solely by means of control of the pneumatic system, to be made subsequently in a silo originally constructed for different data.

In a preferred embodiment it is possible to inspect the inlet channels from the passage In the case of large silos, for instance with capacities of from 20000 to 30000 tonnes, which for reasons of economy are erected on the ground and consequently are provided only with a side outlet or discharge opening for the loose material, the additional provision of a passage of the kind described can be regarded as advantageous for purposes of supervision With silos of this kind it is not always possible to ensure that the material will not undergo physical changes because of its inherent properties, or that, for example, because of leaks in the silo roof or wall which lead to penetration of moisture into the stored material agglomerates which could hinder supply into the homogenising chamber will not be formed.

Such obstructions to the flow of material can be determined by means of inspection openings Furthermore it is possible for obstructions to be cleared from the inlet channels without danger to operators.

The passage and also the homogenising chamber itself are preferably concrete structures, with the passage disposed on the outside of the chamber The passage may alternatively be disposed on the inside of the homogenising chamber It is a question of judgment as to whether the passage should have only one entry from the outer wall of the silo, this entry being, for example, next to the discharge opening, or whether, for example, a second entry is provided on the other side of the discharge opening, The invention is explained more fully below, by way of example only, with reference to the accompanying drawings, in which:Figure 1 is a diametrical cross-section through a silo, and Figure 2 is a horizontal section through the silo on the line A-A in Figure 1.

The silo 1 has a floor 3 provided with air supply channels 2 On the centre of the silo floor is situated a homogenising chamber 4, around which apertures 5 to the inlet channels are provided The floor of the chamber is provided with air supply plates 6, for example known porous ventilation bricks.

A discharge chamber 7 adjoins the side of the homogenising chamber and is provided on the outer wall of the silo with discharge openings 8 disposed at different heights.

An annular passage 11 is disposed round the cylindrical outer wall of the homogenising chamber The annular passage 70 may be reached from outside the silo by way of entrance 12 and passage 13.

Each inlet channel, tapering conically inwards to the homogenising chamber, can be throttled or completely closed by means 75 of a slide valve 14, which can be operated from the annular passageway Apertures 15 in the floor of the annular passage serve both to guide the slide valves and as inspection openings 80 A pipe (not shown) can lead from outside the silo into the upper space of the central chamber to enable additional components to be introduced directly into the homogenising chamber 85 In the roof of the homogenising chamber is provided an opening equipped with a slide valve 9 which can be operated by hand from outside the silo Through this opening loose material lying above the chamber 90 can be fed into the chamber with the aid of air supply elements 10 when the slide valve is open.

The main silo space is filled by means of a loose material distributor spider, diagram 95 matically illustrated at 16.

The passage according to the invention can also be provided in a mixing chamber of the kind described in German Patent Specification No 1507 888 100

The invention provides a means of control by which it is possible to ensure optimum filling of the homogenising chamber and consequently optimum homogenisation, additionally to control of venti 105 lation and independently of factors which cannot necessarily be anticipated during construction of the silo, such as the density and flow behaviour of the loose material.

In some instances a specific amount of 110 premixed loose material is required to be fed into the homogenising chamber before addition of further components in a known manner (see for instance German Patent Application P 2640714 7) and final mixing 115 Interruption of ventilation of the main silo chamber is usually insufficient to achieve such control of feeding, whereas the present invention provides sufficient control of loose material to the homogenising chamber 120

Claims

WHAT WE CLAIM IS:-

1 A silo, for loose material, having ventitition means for fluidising said loose rcaterial, inlet channels through which O'idised loose material is arranged to pass 125 to a homogenising chamber in the silo, each inlet channel having a valve, the homoenising chamber having a passage therea 3 round having an entrance to the outside of the silo and providing access to the valves 130 1 600088

2 A silo according to Claim 1, wherein the valves are slide valves operable from said passage.

3 A silo according to Claim 2, wherein said passage has a plurality of holes in the floor thereof, each adapted to guide a said slide valve and for inspection of its respective inlet channel.

4 A silo according to any preceding Claim, wherein said inlet channels open out into said chamber at positions at or adjacent the floor of the homogenisation chamber and the chamber is circular and situated centrally in the silo.

A silo for loose material, substantially 15 as hereinbefore described with reference to the accompanying drawings.

LLOYD WISE, TREGEAR & CO, Chartered Patent Agents, Norman House, 105-109, Strand, London, WC 2 R OAE.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981.

Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.